Presentation
Case of thymic adenocarcinoma, post-surgery.
Patient Data
A focal hepatic hot spot sign is seen in segment IV of the liver, likely due to recanalization of the veins of Sappey due to underlying SVC obstruction.
A hypodense, hypoenhancing homogeneous mass in the anterior mediastinum retrosternal region with multiple calcific specks in the periphery of the lesion. The mass is encasing and compressing the SVC and azygous vein with luminal narrowing and invasion. Multiple collaterals in the right anterior thorax and paravertebral region. The pulmonary trunk is compressed with a luminal irregular deformity. Posteriorly, the mass extends up to the right lower paratracheal region and inferiorly invades the pericardium.
Case Discussion
The occurrence of the hot spot sign is a result of the blockage of the superior vena cava and the formation of abnormal connections between the superior vena cava and the left portal vein. These connections are formed through the internal mammary and paraumbilical veins along the ligamentum teres. The veins of Sappey are small venous channels or connections between the portal vein and hepatic veins within the liver. These connections are often present in fetal circulation but typically regress and become less prominent as the individual develops. These channels are thought to cause this attenuation defect.
On contrast-enhanced CT of the abdomen, the focal hepatic hot spot sign manifests as a localized region of differential enhancement. This can be observed specifically in the medial segment of the left hepatic lobe, which corresponds to segment IV.
Unable to process the form. Check for errors and try again.